In late July 2016 a group of recreational divers in the Flower Garden Banks National Marine Sanctuary, off the coasts of Texas and Louisiana in the US, noticed something weird. The water was green and hazy instead of the normal clear blue. Large and dense white mats of an unknown substance covered corals and sponges that had previously been healthy. And untold numbers of other reef invertebrates — including brittle stars, sea urchins, crabs, worms, and shrimp — lay dead on the bottom.

It was a bizarre and troubling scene, not least because the reason or reasons for the die-off were unclear — and remain unclear two months afterward. MPA staff are working with partners in government and academia to study the die-off sites for answers (only some areas of the MPA were impacted; other areas remain healthy). The working theory at this point is that a number of stressors likely contributed.

MPA News spoke with the MPA’s research coordinator Emma Hickerson about how management has responded to the event. The interview took place on 18 August.

MPA News: This event took everyone by surprise. What is the process by which Flower Garden Banks management responded to such an unexpected event?

Emma Hickerson: Our first main action was to attempt to determine the extent of the event through direct surveys by research divers. We are still working on completing these surveys — weather has hampered our efforts. We work very closely with partners at academic institutions as well as state and federal agencies to collaborate on key activities, like water sampling, biological sampling, identifying funding sources, etc.

MPA News: Have you been able to rule out any potential causes of the event yet?

Hickerson: No, not yet to be honest. We are still looking at all sorts of possibilities — coming from above, below, or a combination of both.

MPA News: The MPA has asked recreational divers not to enter the affected area. This is to guard against spreading any toxins/microbes to non-affected areas. What precautions are the research divers taking?

Hickerson: After each dive in the affected area we have been rinsing all of our gear in a disinfecting solution. However, the event no longer appeared active by the time of our second response cruise, so the recommendation is no longer in place.

MPA News: Can you estimate how much funding will be needed for this response?

Hickerson: Initial estimates are around US $275,000 for a multi-year response effort. That doesn’t include a lot of in-kind support.

MPA News: Last year the federal government proposed expanding the size of Flower Garden Banks National Marine Sanctuary, potentially to several times its current size of 145 km2. A process to consider that proposal is ongoing. Does this mortality event impact the proposal?

Hickerson: Indirectly. It highlights the fact that in order to catch something like this event, we need to be in the water to see it taking place. If the MPA is expanded to include more reef sites, those sites will become part of the sanctuary’s regular research and monitoring program. We will have more of a chance to catch future events. Additionally if a site is under sanctuary status, it will have more direct access to funds to respond to an unanticipated event like this.

For more information:

Emma Hickerson, Flower Garden Banks National Marine Sanctuary. Email:

For updates on the MPA’s response to the mortality event, including photos and video of the impacted reefs, go to